When Ken
Mastersabsorbed the Orochi power in SNK VS Capcom:
Chaos, he became Violent Ken. This "evil" version of Ken was
inspired by Sennou Ken (which literally means 'brainwashed Ken' in Japanese),
who debuted in Street Fighter II: The Animated Movie where he is being
controlled by M.
Bison.
Violent Ken uses purple flames in his Shoryuken, not unlike Akuma's.

Ryu has an evil
form... so why not Ken?! Ken's evil incarnation in the Street Fighter 2 animated
movie was actually badass if you ask me, so his fighting game iteration was
well-deserved (and it sure took long enough). Violent Ken's poofy white
afro is something else... I think SNK was trolling Capcom a bit there!
^o^ Indeed that is a comical and random hairstyle, especially the way it's drawn in the official SVC: Chaos
artwork (but somehow, also kinda cool?).
On that note, it's also pretty odd that Ken's hair is "back to normal"
in the in-game SVC dialogue artwork and his character sprite. Weird...
(and intriguing?).

Nonetheless, Violent Ken turned out to be a pretty cool character in SVC: Chaos.
Though still a shoto at heart, his powered-up moves and teleporting abilities
definitely put an interesting spin on classic Ken.